Hydraulic duplicating mechanism and exhaust governor



M4 TURCHAN ET AL HYDRAULIC DUPLICATIN-G `MECHANISM AND EXHAUST GOVERNOR y Dec, 25, 1945.

4 Sheets-Sheet l Filed Nov. 5, 1942 Bnventor:

Gtorncg Dec. 25, 1945.

M. TURCHAN ETAL HYDRAULIC DUPLICATING MECHANISM AND EXHAUST GOVERNOR 4 Sheets-Sheet 2v Filed Nov. 5, 1942 l'mventor Gtorneg Dec. 25, 1945. I M, TURCHAN ETAL 2,391,492

HYDRAULIC DUPLICATING MECHANISM AND EXHAUST GOVERNOR Filed Nov. 5, 1942 4 Sheets-Sheet 4 INVENToR. Nfl/vda Tuff/#7N BY ca/Pr/s WAL/(ER Patented Dec. 25, 1945I HYDRAULIC DUPLICATING MECHANISM AND EXHAUST GOVERNOR Manuel Turchan, Dearborn, and Curtis Walker, Detroit, Mich.

Application November 5, 1942, Serial No. 464,690

12 Claims. (Cl. 60-97) 'I'his invention relates to a hydraulic duplicating attachment for a lathe, milling machine, planer, or other device wherein therel may be at least two reciprocable transverse relative feed movements between a cutting device and a work piece support.

It is contemplated also to provide tracer control alternately or intermittently to either of at least two transverse reclprocable relative feed control cylinders, and at the same time provide constant volume feeding to the other of the cylinders not under tracer control. To accomplish this semi-automatically, a manually operable directional control valve is provided of the type fully set out in our co-pending application Serial No. 366,082, filed November 18, 1940, relating to a profiling and contouring tracer mechanism,

one position of manual adjustment thereof, tracer controlled fluid is conducted to one end of for instance the longitudinal feed cylinder, the exhaust from the other side of the piston therein being adapted to return by suitable conduit back to the directional control valve.

At the same time by means of other conduits constant volume fluid is conducted to one end of the cross-feed cylinder, withthe exhaust from the other side of the piston therein returning by conduit to the directional control valve.

By manual adjustment of said directional control valve, in the manner set out in the above mentioned co-pending applications, tracer controlled fluid can be diverted from the longitudinal feed cylinder to one end of the cross-feed cylinder, and at the same time constant vol- `ume fluid will go to one end of the longitudinal feed cylinder.

On further adjustment of the directional con- Vrected to the other end of .the longitudinal feed cylinder.

In this manner it is seen that tracer controlled fluid will be diverted alternately from one feed cylinder to the other and also to either end thereof. The same is also true as to the constant volume feeding. In any case the opposite ends of the cylinders receiving fluid under pressure exhaust fluid back to the directional control valve.

The present invention relates particularly to the subsequent exhausting of this returned exhaust fluid from the directional control valve back to the tracer housing and through an exhaust governor mechanism which regulates the return flow of said exhaust fluid and thence it is conducted back to a fluid sump.

By running exhaust through the tracer controlled governor it will be seenpthat a very effective method is provided for governing feeding ofboth the longitudinal and cross-feed cylinders; because it will be understood that these cylinders can receive tracer controlled fluid or constant volume fluid only as fast as said cylinders can exhaust fluid from the other side of the piston not in communication with said fluids.

Heretofore without effective control of the longitudinal and cross-feeds, cutting tools have been damaged and work spoiled, both of which could have been prevented had an effective method been provided for slowing down or stopping constant feeding at the moment that there was' a change in direction required in the tracer controlled feed.

It is the object of the present invention to provide an exhaust controlling governor within the tracer mechanism and operable thereby for control ing or entirely stopping the exhaust from botli the transverse feed cylinders.

trol valve tracer controlled fluid will be conducted It is the object herein to provide suitable fluid connections from the directional control valve for conducting the exhaust fluid from the tracer controlled cylinder, whichever it may be, back to the tracer valve, together with means for then conducting the same to and through a suitable exhaust fluid governor operable by the tracer mechanism, whence said exhaust uid is returned to a fluid sump disposed in conjunction with a fluid pressure source. y

It is the further object herein to provide suitable uid connections for the directional control valve for conducting exhaust fluid from the constant volume fluid controlled cylinder directly back to the tracer controlled governor, whence it is also returned to said fluid sump.

It is a Still further object of this invention tof provide a back pressure valve means intermediate the tracer controlled exhaust fluid and the governor inlet, and also a back pressure valve means intermediate the constant volume exhaust fluid and the governor inlet, whereby vibration will be eliminated to provide smooth and continuous uninterrupted feeding and cross-feeding; and this as the directional control valve ismanually adjusted for changing tracer control from one feed cylinder to the other and for changing constant volume feeding from one feed cylinder tc the other.

It is the still further object herein to provide a common connection between both of said pres- .sure relief valve means whereby the returned exhausted fluid from both the tracer controlled cylinder and the constant volume controlled cylinder are conducted through a single conduit to the governor inlet within the tracer housing.

It is the still further object herein to provide manually operable uid metering means in a tracer controlled feed line and also in the constant volume fluid exhaust line.

This invention therefore relates to the various elements and their various combinations as more fully set out hereinafter in connection with the accompanying drawings of which:

f Fig. 1 is a diagrammatic view of the hydraulic unit, tracer, directional control valve, transverse feed cylinders. and the hydraulic connections therefor.

Fig. 2 is an elevational partially sectioned view of the tracer illustrating the exhaust controlling governor therein.

Fig. 3 is a side elevational view of the' directional control and reverse valves.

Fig. 4 is a sectional view online 4-4 of Fig. 3.

Fig. 5 is a left end view of the control valve housing with the reversing mechanism removed.

Fig. 6 is a section cn line 6-8 of Fig. 5.

Fig. '1 is a plan view of the plunger for the directional control valve.

Fig. 8 is a section on line 8-8 of Fig. 7.

Fig. 9 is a section on line 9-9 of Fig. '1.

Fig. 10 is a section on line IIJ-I0 of Fig. '1.

Fig. 11 is a section on line II-II of Fig. '1.l

Fig. 12 is a section on line I2-I2 of Fig. 1.

It will be understood that said drawings illustrate merely a preferable embodiment of the invention and that other embodiments thereof are possible and contemplated within the scope of the invention hereinafter described and set out in the accompanying claims.

Referring to the drawings, a hydraulic unit II is indicated having therein a fluid storage sump and means for supplying fluid under pressure out through conduits I2 and I3. Conduit I2 thus supplies fluid under pressure to the tracer housing I4 within which is disposed a longitudinally movable uid control valve piston I5.

Fluid from conduit I2 enters the tracer housing and through a suitable conduit is conducted to the annular opening I6 within piston I5. Tracer spindle I1 longitudinally disposed within the tracer housing I4 projects therefrom having a tracer tip I8 adapted to engage the surface of a pattern I8' sought to be reproduced by a milling machine, lathe or other device.

The upper end of spindle I1 operatively engages the bottom portion of piston I5 with suitable friction minimizing ball races I9 interposed therebetween. Consequently when tracer tip I8 engages an obstruction in the pattern, a longitudinal movement is imparted to said spindle within housing I4 for longitudinally and upwardly actuating a piston I5 within said housing, whereby it is seen that fluid entering annular opening I6 is conducted to annular opening20 whence it is conducted out through fluid outlet conduit 22.

Referring to Fig. 2 a spring member 31 is provisioned around valve stem I5 operatively engaging at its ends the bottom surface of the reciprocable piston I5 andthe adjustable nut 31 whereby with the tracer inoperative said piston is resiliently held slightly below the position shown in Fig. 2. I'his means that fluid under pressure entering the tracer housing and the annular opening I6 is conducted to the annular opening 2I within said tracer housing for communication with the fluid outlet conduit 23.

Referring to Fig. l conduits 22 and 23 are shown interconnecting the tracer housing I4 and the directional control valve 24. It will be noted also that constant volume fluid from the hydraulic unit II is supplied throughv conduit I3 to said directional control valve.

A longitudinal feed cylinder 25 is indicated with a reciprocable piston 2li disposed therein and joined by a suitable connection 21 to a. diagrammatically indicated supporting work table 28 for causing longitudinal feed movement thereof relative to a rotatable cutter.

Conduits 29 and 30 interconnect directional control valve 24 and opposite ends of the longitudinal feed cylinder 25, whereby either tracer controlled fluid or a constant volume fluid may be conducted to either end of said cylinder for operatively moving the piston 26 therein. It will be understood that if fluid is supplied through conduit 29 to cylinder 25, that exhaust fluid from the other side of piston 26 will be returned through conduit 30 back to the directional control valve 24 for further subsequent exhausting in the manner hereinafter set out. Or on the other hand with fluid supplied throughl conduit 30, exhaust will return through conduit 29.

Conduits 3| and 32 also interconnect directional control valve 24 and the opposite ends of the cross-feed cylinder 33 within which is longitudinally and reciprocably disposed a piston 34 operatively connected at 35 to the slide 28 for supporting the work support 28. Consequently it ds seen that reciprocable movement can be obtained for the cross-feed cylinder 33 with either tracer controlled fluid or constant volume fluid being conducted thereto through either conduit 3| or 32.

It will be understood that with fluid entering cylinder 33 through conduit 3| that fluid on the other side of piston 34 will be exhausted out through conduit 32 back to the directional control valve for subsequent exhaustion in the manner hereinafter described. Or with fluid entering cylinder 33 through conduit 32 exhaust will return via conduit 3 I. Referring to the drawings in Figs. 3 to 11, the directional control valve is comprised of a housing 24 with a cylindrical opening 84 therethrough within which is rotatably journaled the valve plunger 53 manually operated by the hand wheel 36.

Annular openings 54, 55, 56 and 51 are provisioned therein in respective communication with the cylinder ports 58, 59, 60 and 6I. Ports 58 and 59 are adapted for connection by suitable conduits 29 and 3l! to opposite ends of a reciprocable work table feeding cylinder, as for instance the longitudinal feed cylinder 25. Ports 60 and 5I are adapted for connection through suitable conduits 3| or 32 'to opposite ends of anto the directional control valve for direction to',

either of the two work table controlling cylinders 25 and 33, and to either end thereof depending upon the relative rotated position of the plunger 53 hereafter described in detail.

Another variable iiuid port 63 is oppositely disposed from opening 62 within valve housing 24, also adapted for vconnection with the above mentioned tracer control valve through conduit 23. Consequently fluid from the tracer`directed to port 62 goes to one end of the longitudinal feed cylinder 25 through conduit 29 going out of housing 24 through port 53, while the fluid on the other side of the piston within said cylinder is forced back through conduit 36 to the control valve through port 59 and thence to port 63. From port 63 in housing 24 said exhaust fluid is conducted back to the tracer control valve through conduit 23 whence it is suitably exhausted to a hydraulic unit II.

If on the other hand the control valve in the tracer I4 is displaced by the operating mechanism within the tracer housing as it engages` the pattern I3',- fiuid from the tracer may get to the directional control valve through conduit'23 and port 63, and thence to the opposite end of the longitudinal feed cylinder 25 through conduit 30; and the exhaust from said feed cylinder on the other side of the piston will then return by conduits 29 and 22 to the tracer I4 through the port 62 in the directional control valve 24.

Referring again to Fig. 5 constant fluid port 64 is seen in the end of valve housing 24 for receiving iiuid under constant pressure which is conducted through a passage 65 to the valve plunger 53 whence it is conducted by said plunger to one end or the other of, for instance, the cross feed cylinder 33 through the outlet 60 in valve housing 24 and conduit 3|. On the other hand exhaust from said cylinder on the other side of the piston therein returns to the directional control valve 24 through conduit 32 to outlet port 6I for communication with the plunger 53 whence it is conducted back to the outlet passage 66 and constant fluid port 61 in the end of valve housing 24, for subsequent exhaustion in the manner later to be described.

On the other hand depending upon the position of the reverse valve hereinafter described, fluid under constant pressure may enter the directional control valve 24 through port 61 and exhaust through port 64.

The flow of constant pressure uid is governed by reverse valve member 14 shown in Figs. 3 and 4. Its housing 69 corresponding in shape to the main valve housing 24 is suitably secured thereto by threaded bolts 69' disposed through openings 13 in the reverse valve housing 69 and main valve housing 24, with a suitable separator or gasket 1| interposed therebetween.

A cylindrical opening 12 is provisioned through housing 63 for rotatably journaling a reverse valve control member 13 manually operable by handle 56. The reverse valve control member 13 cylindrical inshape and shownin Fig. 4, is slotted at 15 and 16, and has formed as a part thereof an nection through conduit I3 with a suitable fluid pressure source within the hydraulic unit II. A similar outlet opening for constant pressure exhausting is provisioned at 13 for exhausting fluid from the particular cylinder at the moment under constant feed control through conduit 41 back to the tracer I4 for subsequent exhausting in the manner hereinafter set out.

Both inlet 16 and outlet 19 communicate with the interior central opening 12. A reversing port 96 is shown in Fig. 4 joining passage 9| to the central opening 12. With the rotatable reverse valve member 13 in the position shown in Fig. 4, iluid underconstant pressure from inlet 19 is conducted through slot to the passage 9| and port 90.

Similarly a reversing port 32 is provided in housing 69 with a passage 93' joined thereto communicating with the central opening 12. In the position of the rotatable reverse valve member 13 as shown in Fig. 4 port 92 is an exhaust opening for the other side of the cylinder at the moment receiving constant pressure fluid. Port 92 and passage 93' thus conduct exhaust fluid through the central opening 12 through the slot 16 and to the reverse valve exhaust opening 19 whence it is -suitably conducted away through conduit 41.

It is seen from Fig. 4 that by clockwise movement of the reverse valve member 13 a quarter of a turn fluid under pressure will be delivered via inlet 19 and slot 15 and through passage 93' to the pressure port 92. And in a similar manner the exhaust fromthe other side of the cylinder under constant pressure feeding will return through port 86, passage 9|, slot 16 and outletv opening 19 for disposal through conduit 41.

Thus it is seen Athat by rotation one quarter of a. turn of re'verse valve member 13 that fluid under constant pressure is directed to either port 1 93 or 92, thus providing a means for quickly reversing the direction of movement of the feed cylinder which happens to be under constant fluid control. For instance in traveling around a work piece it may be desirable to back up a short distance from any point along the circumambulatory traverse. v

With the reverse valve housing 14 secured in place against the left end of the main valve housing 24 by bolts 69' it is seen that reversing ports 63 and 32 in housing 14 coincide in communieating relation with constant vfluid ports 61 and 64 respectively in main valve housing 24. Thus fluid under constant pressure independent of the operation of the tracer I4 may be directed through either port 64 or 61 or'changed at` will from one to the other.`

Valve housing 24 also has a tracer controlled fluid source coming in at opening 62 from conduit 22 and returning to the tracer control valve through variable fluid port 63 and conduit 23; or fluid may come from the tracer through port 63 and return through port 62 depending upon the operation of tracer I4. On theother hand four cylinder ports 53, 59, 66 and 6I are provisioned within' the valve housing with suitable conduits 29, 36, 3| and 32 joined to each providingfiuid communication to both ends of .each work table controlling cylinders 25 and 33 respectively.

A manually rotatable plunger 53, shown in Fig.

v'1, is Joumaled within cylindrical opening u for directing the constant pressure fluid coming into the directional control valve housing 24 at either port 64 or 61, out through any of the cylinder ports 58, 5 9, 60 or 8|, and the tracer controlled fluid pressure source coming into the valve housing at ports 62 or 63, out through any of the valve cylinder ports 60 or 6I and 58 or 59. Said control valve also provides at the same time exhaust connections for the other two ports back to one or the other of the constant pressure ports 64 and 61 and also to one or the other of the tracer controlled iiuid ports 62 and 63.

Said plunger 53 has provisioned longitudinally therein non-communicating passages 85, 86, 81 and 88 all terminating-,at one end of the plunger in the four radially positioned passages 85', 88', 81 and 88', each of which is adapted for progressive communication with each of the ports 82, 83, 64 and 61 respectively as the plunger is manually rotated one-fourth of a turn at one time by hand wheel 36.

A plurality of annular recesses 89, 90, 9| and 92 are provisioned within plunger 53 to coincide with the corresponding annular recesses 54, 55, 56 and 51 on the inside of the valve housing 24 as shown in Fig. 6.

Longitudinal opening 85 terminates at outletV 93 within annular opening 89 to establish communication with the corresponding cylinder port 58 within the annular recess 54. openings 86, 81 and 88 are all of varying lengths from opening 85 and likewise respectively terminate at outlets 94, 95 and 96 within annular openings 90, 9| and 92, to establish communication respectively with the corresponding cylinder ports 59, 60 and 6I within the annular recesses 55, 56 and 51 in thvalve housing 24.

Consequently in turning plunger 53 a quarter of a turn at a, time it is possible to provide communication from any one of the ports 62, 63, 64

Longitudinal and 61 in the control valve to any desired cylinder port 58, 59, 60 or 6I in the valve housing for providing control to any particular end of either the longitudinalor cross feed cylinders; and at the same time also providing communication from the other inlets to each of the other ends remaining in said cylinders.

quarter of a turn counter-clockwise constant feed is again reversed in the longitudinal feed cylinder 25 asilrst set out. Throughout this operation there has been no change in the tracer controlled fluid supply to the cross feed cylinder 33 through conduit 32 at one end thereof and exhaust therefrom at the other end through conduit 3|.

In progressively traversing around a work piece in a circumambulatory path if it is desired to change the constant feed from the longitudinal feed cylinder 25 to the cross feed cylinder 33, with tracer control changed from the cross feed cylinder to the longitudinal feed cylinder 25, all that is necessary is to rotate the plunger 53 a quarter of a turn clockwise. y

Constant feed from the reverse valve at 18 goes via 15, 8|, 80, 61, 66, 88, 96 and 8| and through conduit 32 to one end of the cross feed cylinder 33 while exhaust therefrom on the other side of said cylinder goes back to the directional control valve via. conduit 3|, 60, 95, 81, 65, 64, 82, 83', 16 and 19.

At the same time tracer control goes to longitudinal feed cylinder 25 via conduit 22, 62, 85, 93, 58 and conduit 29; and the exhaust from the other side of said cylinder returns via conduit 30, 59, 94, 86, 63 and conduit 23 back to the tracer I4 for exhausting.

Again constant feed, now inthe cross feed cylinder 33 may 'be reversed merely by rotating handle 50 of the reverse valve 14 one-quarter of a iishlurn clockwise in the manner hereinabove set ou Thus it is seen that a versatile directional control and reverse valve is provided for goveming longitudinal and cross feeding of the work piece supporting table with respect to a rotatable cutter.

"M/ Constant feeding may be changed from longitudinal feed in one direction to cross feeding in one direction. By further operation of the hand vwheel 36 constant feed may be again directed to the longitudinal feed cylinder in the opposite di- For example fluid under constant pressure through conduit I3 from the hydraulic unit II duit 32 to one endof for instance, the'cross feed;

The exhaust from the other side cylinder 33.

thereof goes back via conduit 3| to cylinder port 60, 95, 81 and 63 and back to the tracer valve via conduit 23 for exhausting.

In operation by turning handle 50 of the reverse Vvalve a quarter of a turn clockwise, constant pressure from conduit I3 to the longitudinal feed cylinder 25 is reversed or sent to the other end thereof through conduit 30 via 18, 15, 83', 82, 64, -65, 85, 93, 58 and conduit 29. And at the Sametime exhaust returns from the opposite end of said cylinder via conduit 30, 59, 94, 86, 66, 61, 80, 8|, 16 and 19 and thence through conduit 41 back lto tracer I4.

. By turning the reverse valve handle back onerection: and by another quarter turn of the hand wheel constant feed could go to the cross feed cylinder in the opposite direction.

The reverse valve above described is also adapted to reverse constant feeding in any one cylinder at any time without further operation of the control valve hand Wheel 36, which normally would require several adjustments for accomplishing the same result.

A packing gland 91 is shown in Fig. 3 suitably bolted on one end of the valve housing 24, with .the operating shaft 98 forming a part of the plunger 53 journaled therethrough. An adjust- Y ing nut 99 is disposed within the end of the packing gland for adjusting the same. Similarly a packing gland |00 is provisioned upon the outer end (of the reverse valve housing 14 suitably secured thereto. The actuating shaft 11 for the reverse valve member 13 is rotatably journaled through the packing gland |00 and an adjusting nut IOI is provided as shown.

' With the reverse valve handle turned at any time a quarter of a turn to reverse the direction of feed of the cylinder under constant feeding, continuous traverse in a circumambulatory path around the work may be continued in that reverse direction merely by operating the hand Wheel 36 in quarter turns progressively in the opposite direction.

rI'he directional control valve 24 is fully described in our co-pending above referred to applications has provisioned thereon a manually operable means 36 for rotatably positioning the valve member therein. Said rotatable valve member is therefore adapted to provide tracer controlled uid to one end or the other of either cylinder as for instance the longitudinal feed cylinder 25; and at the same time constant volume fluid from conduit I3 is conducted through said directional control valve to one end or the other of for instance the cross-feed cylinder 33.

By progressively adjusting the manually operable member 33 of the directional control valve tracer controlled fluid may be diverted from one feed cylinder to the other and to either oi' the ends thereof. Likewise it will be understood that constant volume fluid may be diverted from one feed cylinder to the other and also to either of the ends thereof. l

In any event thel exhausted fluid from both feed cylinders must return to the directional control valve 24 whence the same is returned to the tracer housing I4 through the exhaust governor hereinafter described in detail.

Referring to Fig. 2 annular opening 2I is conturning said constant volume ilid exhaust through conduit. to the governor inlet opening 43.

And in a manner similar to the exhausting of the tracer controlled 'fluid exhaust, the constant volume fluid exhaust travels through opening 44 and the governor outlet opening v45 and thence l work; and with iiuid flowing out through conduit nected by conduit 23 for delivery of fluid to the I v duit 22 back to the tracer housing I4 and to annular opening 20 therein. Control governor opening 44 being enlarged at its top and bottom, it is seen that its upper edge overlaps the lower edge of annular opening 45; and that its lower edge overlaps the upper edge of annular opening 43. Thus in the neutral position shown in Fig. 2 of valve I5 exhaust iluid is free to flow through openings 43. 44 and 45.

Also slight elevation or depression of valve I5 only partially restricts the flow of fluid through governor openings 43, 44 and 45. However the more extreme upward movement of valve I5 results in opening 44 being entirely cut oil.' from opening 45, so that uid can go through opening 43 to 44, but cannot enter governor outlet 45.

It will be seen that with the piston I5 in its initially spring depressed position, i. e. slightly below the position shown in Fig. 2, annular opening 20 is in communication with the annular exhaust opening 38 within piston I5. Consequently exhaust uid which returns through conduit 22 goes through annular openings 20 and 33 and thence through the exhaust conduit 39 and the back pressure relief valve 40 connected thereto.

' Said exhaust uid 'enters'the T connection 4I and travels through conduit 42 back into the` tracer housing for communication J-with the governor inlet opening 43. Even in the slightly depressed position of piston I5 exhaust fluid through conduits 3I and 22 from the other 'side of cylinder 33 flows from governor inlet 43 to annular opening 44 in the tracer housing whence it flows into the annular governor outlet opening 45, which is in turn joined by conduit 46 for returning the exhaust uid back to the storage sump within the hydraulic unit II. y

, During this operation with the valve I5 and the spindle I1 and tracer tip I3 slightly depressed by resilient action of spring 31, constant volume fluid exhaust is returning to the tracer housing I4, through the conduit 41 from the longitudinal Y feed cylinder 25. Conduit 41 joins back pressure 23, the cross-feed cylinder 33 for instance is causing cross-feeding of the work table slide 23' until the tracer tip I3 engages the pattern. This causes spindle I1 to elevate slightly against action of the spring 31 until piston I5 assumes the position shown 1n Fig. l2. At this instant uuid outnow to conduit 23 is stopped thus preventing further cross-feeding of piston 34.

It will be noted however that the constant volume exhausting from the longitudinal feed cylinder 25 and conduit`41 may still go through the governor inlet 43, opening 44, governoroutlet 45, and conduit 46 for return to the hydraulic unit II.

Just as soon, however, as further longitudinal constant feeding causes tracer tip I3 to engage a slight obstruction it is desirable to definitely slow down said constant feeding until there has been a reversal of vcross-feeding to the extent that spindle I1 and piston I5 can again assume a neutral position as shown in Fig. 2.

Therefore on tracer tip I8 engaging an obstruction spindle I1 and piston I5 are elevated several thousandths of an inch above normal position partially closing oil the governor outlet opening 45, and slowing down constant longitudinal crossfeeding. This is accomplished by limiting the constant volume exhaust which will move through the exhaust governoroutlet 45.

Now in elevated 'position of piston I5 uid under pressure from conduit I2 is free to enter annular opening 20 causing fluid to flow out through conduit 22 to the directional control valve 24. The latter directs this iluid through conduit 3| to the opposite end of the cross-feed cylinder 33.

This immediately starts a cross-feeding in the opposite direction gradually permitting spindle I1 and piston I5 to descend rto neutral positionuntil no further upward pressure is exerted upon spindle I1 other than that required to keepthe piston in a neutral position.

With fluid under pressure from the tracer going to cylinder 33 through conduit 3 I, exhaust uid is returned viaconduit 32 to the directional control valve and thence through conduit 23 back to annular opening 2I. With thepiston I5 elevated annular openingv 2| is in communication with the annular exhaust opening 49 which in turn joins the exhaust conduit 35 for subsequent exhausting through the governor openings 43, 44 and 45.

By the provision of the above described means for causing both exhausts, i. e. from the tracer controlled cylinder and from the constant vol ume fluid controlled .cylinder to return through governor inlet 43, opening 4'4, and' governor outlet 45 for subsequent exhaustion back to the hydraulic unit, it is seen that at the moment any obstruction in the pattern is reached causing an upward movement of the piston that the governor outlet 45 partially closes slowing down all relief valve 48 and the T connection 4I also re- 75 feeding movement'of either cylinder. This prevents the breaking of th cutter or damaging of the work piece; and also provides that increment of time which is necessary to obtain the reversal of feeding so that the tracer tip I8 overcomes the obstacle in the pattern and the piston I is permitted to return to neutral position.

It will be understood that this operation is the same with the tracer controlling longitudinal feeding and with constant feeding in the crossfeed cylinder, all of which is accomplished by the manual adjustment of wheel 36 of the directional control valve 24. l

The invention therefore provides a safety mechanism for directing the exhausts from both transverse feed cylinders through a tracer controlled governor, so thatfor any change in direction required of the cylinder under tracer control. both feed movements are slowed down until that change can be effected.

When the invention herein is employed in conjunction with two directional contouring and profiling as fully set out in our co-pending application Serial No. 366,082, it is desired that the cutter relatively walk entirely around the work piece in a path corresponding to the path taken by the tracer tip around the patternl sought to be reproduced in the work.

As set out therein the directional control valve is intermittently manually actuated for alternately changing tracer control from one feed cylinder to the other as the cutter approaches certain critical points in its relative circumambulatory path around the work. For instance, tracer control is directed to the feed cylinder which at the moment governs the greatest change in direction of relative movement between the cutter and the work. Also the feeds are reversed from one end of the feed cylinders to the other.

Consequently with such continuous operation of the tracer it becomes necessary to incorporate a safety device therein to regulate and govern l the return of exhaust fluids from these cylinders.

By so controlling the exhausts therefrom it is seen that a. very effective control of feed movement may be obtained, which is directly responsive to movements of the tracer spindle as it engages a pattern.

As set out in our co-pending application Serial No. 366,082, the directional control valve 24 must be under the constant supervision of a skilled operator. This means that if the cutter is to progress in a circumambulatory path with respect to the work, the rotatable valve member within said directional control valve must be intermittently and progressively rotated by the actuating handle 35. A

As above described, by actuating member 36 tracer control is alternately changed from one cylinder to the other, and alternately changed from one end of each cylinder to the other end thereof. At the same time constant volume feeding is intermittently and alternately changed from one cylinder to the other, and also from one end of each cylinder to the other.

By this operation of the directional control valveas set out in detail in the above mentioned co-pending application, a smooth and continuous relative circumambulatory traverse of the work by the cutter is obtained. If however the operator should not be alert. or has his attention otherwise directed, he may not properly operate the directional control valve 'actuating means at the proper time. But for the above described governor this inattention would cause the breaking o of the cutter tool, or possible damage to the work piece.

However with the governor mechanisms 43, 44 and 45 controlling the exhausts at all times from both cylinders this danger is eliminated in the following manner. With the tracer spindle I1 engaging a sudden obstruction, the same is projected upwardly but because the directional control valve member 35 has not been properly aci--` justed, the reversal of feed movement caused by upward movement of valve piston I5 does not eliminate the obstruction to the tracer tip I8 but merely causes further upward movement of piston I5.

'I'his immediately closes governor opening 44 from the governor inlet 43 with the result that all feeding in both directions is immediately stopped. It will be understood that nprmal tracer movement causes a mere reversal in the cross feeding, for instance, that the movement of the piston I5 is slight and consequently the governor is only slightly restricted, at most merely slowing down the relative feed movements.

However when the operation is not normal due to inattention of the operator, the movement of piston I5 upward upon the tracer tip I8 reaching an obstruction in the pattern is greater which in turn immediately completely constricts the communicating openings 43, 44 and 45 through the governor.

This stops all exhausting from both feed cylinders which results in immediately stopping all feeding movement. Thus the operator is given an opportunity to reset the directional control valve before again starting a relative traverse of the cutter with respect to the work.

It will benoted that the two back pressure valves 40 and 48 are interposed between the two return exhaust conduits 41 and 39 and the governor inlet opening 43. It was found that with these back pressure valves absent that considerable vibration occurred in conjunction with the operation of the pistons 25v and 34 within their respective cylinders. By employing these back pressure release valves, a cushion is provided or a certain amount of resistance set up against the return iiow of the exhaust fluid from the cylin-l ders, which has been found to eliminate vibration and permit a very smooth operation thereof.

It will be noted that both exhausts after going through the back pressure valves l4I) and 43 go into the T connection 4I for subsequent entry into the governor inlet 43. This provides a simplified means for joining the two exhausts from the tracer controlled cylinder and from the constant volume iiuid control cylinder, and returning said exhaust together to and through the tracer con-trolled governor for return to the hydraulic storage sump. It is seen that back pressure relief valves 4u and 48 are respectively provided with spring tension adjusting screws 40 and 48'.

Referring to Fig. 1 a reversing mechanism 50 is provisioned upon one end of the directional control valve, whereby the direction of flow of constant volume fluid from conduit I3 may be reversed. This will cause, when operated manually, a reversal only in the direction of feed of the cylinder at the time under constant feeding. This enables the operator to backup the work relative to the cutter at any point along the work without otherwise manipulating the manual control 36 to a reverse position.

Referring to Fig. 1, manually operable metering valves 5I and 52 are respectively interposed in the tracer controlled duid supply Aor exhaust conduit 23, and the constant volume exhaust line 41. Thus at any moment the operator may vary the volume of fluid flowing therethrough to speed up or slow down either or both cylinder feed movements.

For instance, in traveling a substantially straight longitudinal traverse under constant feeding, where the cross-feeding will be slight, it is desirable to speed up the longitudinal feed movement throughout substantially the length of the traverse. ally adjusting the metering valve 52 in theconstant volume exhaust line 41. Or on the other hand the feed in the other direction can be ac celerated by manually operating metering valve '5| in line 23.

Having described our invention reference should now be had to the claims which follow -for determining the scope thereof.

said directional control valve and said tracer, a y

tracer actuated exhaust fluid governor valve, and means for conducting 4the exhausts from both feed cylinders through said governor valve Whereby upon movements of said tracer actuated governor restricting the openings therein, relative feed movements may be controlled.

,2. In combination, a fluid pressure source, a tracer actuated fluid control lvalve, a directional control valve adapted to direct tracer controlled fluid alternately to either end of either one ofv two transverse feed cylinders, and constant volume uid to either, end of the other feed cylinder, conduits for supplying and exhausting tracer controlled fluid to and from said directional control valve, a conduit for supplying constant vvolume fluid to said directional control valve, a constant volume uid exhaust conduit between said directional control valve and said'tracer, an exhaust fluid governor valve forming a part of said tracer actuated valve, and means for conducting the exhausts from both-feed cylinders through said governor valve whereby upon movements of said tracer actuated valve, restricting the openings through said governor valve, relative feed movements may be controlled.

3. In combination, a tracer actuated fluid control valve, a directional control valve adapted to alternately direct tracer controlled fluid from a pressure source to either end of either one of two transverse feed cylinders, and constant volume fluid from said pressure source to either end of the other feed cylinder, a tracer actuated pressure source to either end of either one of two transverse feed cylinders, and constant volume fluid from said pressure source to either This is done merely by manuend of the other feed cylinder, an exhaust fluid governor valve having fluid openings therein and forming a part of said tracer actuated valve, and exhaust conduits from said directional control valve for conducting the exhausts from both feed cylinders through said governor valve whereby upon movement of said tracer actuated valve causing a restriction in said openings, relative feed movements may be stopped.

5. In combination, a tracer actuated fluid control valve, a directional control valve adapted to alternately direct tracercontrolled fluid from a pressure source to either end of either one of two transverse feed cylinders, and constant volume fluid from said pressure source to either end of the-other feed cylinder, a tracer actuated exhaust nuid governor valve having fluid openings therein, exhaust conduits from said directional control valve for conducting the exhausts from both feed cylinders through said governor valve whereby upon movements of said vtracer actuated valve causing a restriction in 'said openings, relative feed movements may be controlled, and back pressure relief valves interposed in said exhaust conduits.

6. The combination, a tractor actuated fluid control valve, a directional control valve adapted to alternately direct tracer controlled uid from a pressure source to either end of either one of two transverse feed cylinders, and constant volume uid from said pressure source to either end of the other feed cylinder, a tracer actuated exhaust iuid governor valve having fluid openings therein, means for conducting the exhausts from both feed cylinders through said governor valve whereby upon movements of said tracer ac- 40 tuated valve causing a restriction in said openexhaust fluid governor valve, having fluid openings, relative feed movements may be controlled, said means consisting of separate conduits from the directional control valve conducting exhaust fluid from each of said feed cylinders converging at a T pipe connection, a conduit therefrom to said governor valve, and back pressure relief valves interposed in said exhaust conduits.

7. I n combination, a tracer actuated uid control valve, a direction control valveadapted to alternately direct tracer controlled fluid from a pressure source to 'either end of either one of two transverse feed cylinders, means for alternately conducting constant volume fluid to either end of the other feed cylinder, a tracer actuated exhaust fluid governor valve having openings therein and exhaust conduits from said directional control valve for conducting the exhausts from both feed cylinders through said governor valve whereby upon movements of said tracer actuated. valve causing a restriction in said opening, relative feed movements may be controlled.

8. In combination, a tracer actuated fluid control valve, a direction controlvalve adapted to alternately direct tracer controlledl fluid from a pressure source to either end of either one of two transverse feed cylinders, means for alternately conducting constant volume fluid to either end of the other feed cylinder, a tracer actuated exhaust iluid governor valve having openings therein, exlhaust conduits from said directional ,control valve for conducting the exhausts from both feed cylinders through said governor valve whereby upon movements of said tracer actuated valve causing a restriction in said openand back pressure relief valves interposed in said exhaust conducting means.

9. In combination, a tracer housing, a spindle disposed therein and projecting outwardly therefrom, adapted to longitudinal movement upon receiving a thrust from a pattern, a fluid control valve operably connected to said spindle, a directional control valve adapted to alternately direct tracer controlled fluid from a pressure source to either end of either one of two transverse feed cylinders, and constant volume fluid from said pressure source to either end ofthe other feed cylinder, a tracer actuated exhaust iuid governor valve, having huid openings therein, exhaust conduits from said directional control valve for conducting the exhausts from both feed cylinders through said governor valve whereby upon movement of said tracer actuated valve causing a restriction'in said openings, relatlve feed movements may be controlled.

10. In combination, a tracer actuated huid control valve, al directional control valve adapted to alternately direct tracer controlled fluid from a pressure source to either end of either one of two transverse feed cylinders, and constant volume iiuid from said pressure source to either end of the other feed cylinder, a tracer actuated exhaust fluid governor valve having uid openings therein, exhaust conduits from said directional control valve for conducting the exhausts from both feed cylinders through said governor valve whereby upon movement of said ing. relative feed movements may be controlled,

tracer actuated valve causing a restriction in said openings, relative feed movements may be stopped, and manually operable metering means for limiting the flow of tracer controlled and constant volume fluid to said directional control valve.

11. In combination, a tracer actuated iiuid control valve, a directional control valve adapted to alternately direct tracer controlled fluid from a pressure source to either end of either one of two transverse feed cylinders, and constant volume fluid from said pressure source to either end of the other feed cylinder, a. tracer actuated'exhaust fluid governor valve having fluid openings therein, separate exhaust conduits from each of said feed cylinders converging at a T pipe connection, a conduit therefrom to said governor valve whereby upon movements of said tracer actuated valve causing a restriction in said openings, relative feed movements may be controlled.

12. In combination, a fluid pressure source, a tracer actuated uid control valve, a directional 'control valve adapted to alternately direct tracer 30 sure source. 

